Apparatus and method for manufacturing a frozen confectionary product

ABSTRACT

The invention relates to apparatus and method of making a frozen confectionary product such as ice cream or sorbet in which a confectionary mix is churned in a vessel whilst a liquid gas such as liquid nitrogen is added. Existing churning apparatus moves a stirrer through the ice cream mix in an epicyclical motion. This tends to splash liquid nitrogen so that it evaporates without contributing to the freezing of the ice cream. In the improved mixing method, the stirrer is repeatedly drawn against the inside wall(s) of the vessel. This reduces splashing of the liquid nitrogen. The drawing action also removes build up of frozen confectionary product on both the stirrer and the vessel walls and allows unfrozen confectionary mix to move to the edges of the vessel and be preferentially frozen.

The present invention relates to apparatus and method for making afrozen confectionary product.

U.S. Pat. No. 7,754,266 describes a method of making ice cream in whichliquid nitrogen is added to an unfrozen ice cream mix whilst beingchurned. The ice cream is made in situ within a paper cup.

Liquid gas cannot be added into the bulk of the ice cream mix as theresulting rapid expansion of gas causes the ice cream mix to beprojected out of the cup. Consequently, liquid gas is poured on top ofthe ice cream mix, freezing its upper surface only. A centrifugal actionfrom the rotation of the vessel forces the liquid-gas outwardly. Thiscauses a build up of hard frozen ice-cream around the inside wall of thecup.

The ice cream tends to freeze preferentially onto the mixing instrument.This clogging results in the frozen mix being moved around the cup onthe mixing instrument rather than being mixed.

The epicyclic motion of the mixing instrument tends to splash liquidnitrogen sitting on the surface of the ice cream mix. A significantproportion of the splashed liquid gas is wasted as it evaporates awayfrom the ice cream mix without contributing to the freezing process.

According to a first aspect of the invention there is provided a methodof making a frozen confectionary product in which an unfrozenconfectionary mix, agitated within a vessel, is cooled and frozen by aliquid gas; wherein an agitator agitating the mix has a motion whichcomprises repeatedly drawing the agitator substantially against aninside wall of the vessel.

The invention is particularly beneficial in the manufacture of personalsized portions of confectionary mixture as it significantly reduces theamount of splashing of both liquid gas and confectionary mix.Additionally, the contact between the agitator and the vessel removesbuild up of frozen mix on both parts thereby allowing: unfrozen mix tomove to the edges of the vessel and be preferentially frozen, andreducing the likelihood of mix clogging onto the agitator.

It is preferred that the motion comprises repeatedly drawing theagitator substantially against a side wall of the vessel.

It is preferred that the agitator is moved relative to the vessel inorder to contact the vessel wall, however it may be possible to move thevessel to the agitator, or both the agitator and vessel in order toachieve the same effect.

Preferably the vessel is rotated in order that a subsequent motioncauses the agitator to draw against a different portion of the insidewall of the vessel. In this preferred method, substantially all of thecircumference of the inside wall is scraped by the agitator.

It is preferred that the agitator is drawn downwardly against the sidewall of the vessel towards the base of the vessel. Preferably contact ofthe agitator and the vessel's inside wall starts above or substantiallynear the surface of the confectionary mix, and the agitator then drawndownwardly through the confectionary mix.

In order to increase the amount of mixing, it is preferred that themotion comprises an opposing movement in which the agitator moves awayfrom the inside wall of the vessel. Preferably this is combined with anupward movement in order to bring the agitator out from theconfectionary mix.

The supply of liquid gas in the apparatus described in U.S. Pat. No.7,754,266 comprises a dewar vessel 6 having an outlet at its bottom anda valve 10, having a relatively large thermal mass, for controlling theflow of liquid gas through the outlet under gravity. Each time valve 10is opened, the liquid gas the first portion of fluid will cool the valve10 down to temperature. A portion of the liquid is wasted as itevaporates during cooling of the valve 10. This also creates a delay inthe supply of liquid gas to the vessel until the valve has cooledsufficiently.

According to a second aspect of the invention there is provided areservoir for holding a liquid gas the reservoir having:

-   -   an outlet for allowing liquid gas to flow out from the        reservoir;    -   a valve, having a valve body, to control the flow of fluid        through the outlet, the valve body being located within the        reservoir so that when the reservoir is filled at least one        outer surface in contact with liquid gas within the reservoir.

Because the valve body is located within the reservoir, in contact withthe liquid gas, the valve body is cooled down substantially to thetemperature of the liquid gas. When it is required to dispense an amountof liquid gas from the reservoir, none of the dispensed liquid is wastedthrough cooling of the valve body. As well as reducing waste of liquidgas, it also reduces the delay between opening the valve and liquid gasbeing dispensed to the confectionary mix.

It is preferred that the valve body is arranged to be at least partlysubmerged in the liquid gas.

The invention will now be described by example with reference to thefollowing figures in which:

FIG. 1 is a schematic of apparatus for manufacturing a frozenconfectionary product;

FIG. 2 is a perspective view of the mixer and vessel of FIG. 1;

FIG. 3 is a further perspective view of the mixer and vessel of FIG. 1;

FIGS. 4A-4H are side elevations of a mixer and vessel illustrating themotion of the agitator during mixing; and

FIG. 5 is a schematic of apparatus for manufacturing a frozenconfectionary product which includes multiple mixers.

Referring to FIG. 1 there is illustrated schematically, apparatus formaking a frozen confectionary product, such as ice cream. In overview,the apparatus comprises a paper cup 26 (or other vessel) for holding asingle portion of confection mix 26A and a mixer 20 having a mixingelement 24 for mixing the confection mix within the cup 26 and means tosupply a liquid gas into the cup 26 to freeze the confectionary mix. Indetail, there is shown a dewer 1 holding a supply of liquid gas,commonly liquid nitrogen, a pump 2 for pressurizing the liquid gaswithin the dewer 1, a thermally insulated conduit 3 for carrying liquidgas under pressure from the dewer 1 to a reservoir 4. The reservoir 4comprises a thermally insulated container. In this instance thereservoir 4 comprises nested walls 4A, 4B, the cavity 4C therebetweenbetween being partially evacuated. The reservoir 4 comprise an inlet 5for receiving liquid gas from dewar 1, and a thermally insulated conduit6 passing through walls 4A, 4B forming an outlet. Conduit 6 guides flowof the liquid gas from the reservoir 4 to mixing cup 26. In this examplethe conduit 6 passes through lower portion of walls 4A, 4B, though inalternative embodiments it may pass through an upper portion.

Within the reservoir cavity formed within wall 4B sits a valve 7comprising an inlet conduit 7A, valve casing 7B and valve element 7Coperated by a solenoid mechanism 8. A further opening is formed in upperportions of walls 4A, 4B which provides an air vent 9. The vent may beopened or closed by a float valve 10.

In operation liquid gas pressurised within dewar 1 flows along conduit 3into and fills reservoir 4. The vent 9, which is open during the fillingprocess, allows evaporated liquid gas to escape from the reservoircavity 4. This is particularly important at the start of the fillingprocess because a substantial volume of gas will be generated as theinner wall 4B and the valve 7 are cooled to the temperate of the liquidgas. Filling of the reservoir 4 continues until the pressure within thereservoir substantially equals that of the liquid gas flowing from dewar1.

When it is wished to dispense liquid gas from the reservoir 4, solenoidmechanism 8, which lies at least partly outside of the reservoir cavity,is activated moving valve element 7C to allow a flow of liquid gas underpressure through outlet 6. Because the liquid gas flows under a pressuregreater than gravity, it is possible to have the outlet of the reservoir4 formed in an upper part of the reservoir 4, or/and for the outlet ofconduit 6 to be located above reservoir 4. This may be particularlyadvantageous where it is required that the reservoir 4 be held below thevessel 26.

Valve 10 may also be periodically opened (manually or otherwise) toallow venting of gas, such as may be required if liquid gas is heldwithin the reservoir 4 for a time.

Mixer 20 comprises stand 21 which carries a cantilevered arm 22. Arm 22is carried by stand 21 via a linking mechanism 23 allowing arm 22 torotate relative to stand 21. Mounted onto the free end 22A of arm 22 isan agitating assembly comprising an agitation element 24 and motorassembly 25.

In an operating position, arm head 22A sits above vessel 26 so that theagitation element 24 extends into the vessel 26. The vessel 26 issupported on a motorised support 27 that in operation causes the vessel26 to rotate about a vertical axis as viewed in FIG. 1 passingsubstantially through the centre of the cup 26.

As shown in FIG. 2, the agitating assembly is mounted onto arm head 22Aabout pivot 28 which allows the agitating assembly to rotate relative toarm 22 about an axis X-X. The extent of rotation is restricted by a stop29 provided on the agitating assembly that passes through a slot 30 ofthe arm. A spring 31 (see FIGS. 1 and 4A) is attached between stop 29and an anchor 32 on the arm 22. The spring 31 acts to bias the agitatingelement 24 towards a substantially vertical orientation.

As seen best in FIG. 3, the end of the agitating element 24 comprises anelongate portion 24A terminating with an enlarged head 24B having aserrated outer edge 24C to assist removal of frozen confection productfrom the walls of the vessel 26. The motor 25, when in operation, causesthe agitation element 24 to rotate about an axis running substantiallythrough the length of the elongate portion 24A

As illustrated in FIGS. 2 and 3 movement of the arm is effected by amotor 230 mounted onto supporter 21. Through a gearing mechanism 231operation of the motor 230 turns radial arms 232, 233 in like directionsabout pivot points 234, 235 located towards at one end of each radialarm 232, 233. Pins 236, 237 located towards the other end of the radialarms 232, 233 provide pivotal mountings for arm 22.

When motor 230 operates, the linking mechanism 23 provides a motion tothe agitating element 24 described below and illustrated in FIGS. 4A-4H.

From the initial position illustrated in FIG. 4A, rotation of the tworadial arms of the linking mechanism causes the agitating element 24 tomove downwards and towards the right hand side of the cup 26 as viewedin FIG. 4B until it makes contact with the inside wall of cup 26.Further movement of arm 22 to the right causes the agitating elementassembly to rotate about pivot 28 so that agitating element 24 maintainscontact with inner wall FIGS. 4C, 4D as the agitator moves downwardstowards the base of the vessel 26. This scrapes solidified (frozen)confectionary mix 26A which preferentially forms on the edges of the cup26, and the upper surface of the vessel 26 and pushes it down towardsthe bottom of the vessel 26. Once at or towards the base of the cup 26,the agitating element 24 moves away from the wall towards the centre ofthe cup 26 and simultaneous upwards thereby dragging with it, with theaid of the flange of broaden head 24B, unfrozen confectionary mix 26A tothe surface (FIG. 4E, 4F). Once the agitation element 24 loses contactwith the wall of cup 26, spring 31 causes the agitation assembly toassume its original orientation. The agitation element 24 is lifted outof the confectionary mix to it original position shown in FIG. 4A. Theabove movements all occur in a single vertical plane.

In order that ice cream is scraped from substantially all surfaces ofthe cup 26, the cup 26 is caused to rotate about axis Y-Y (see FIG. 3).Scraping of the ice cream from the surface of the vessel is assistedthrough the rotation of agitating element 24 about it primary axis.

The upstanding wall of a paper cup 26 is commonly formed from a singlesheet of paper product which is curved with one edge overlapping andjoined (usually glued) to an opposite edge. To ensure that this rotationdoes not cause damage to this join, the rotational direction of theagitating element 24 is selected to ensure that the edge of theagitation would first contact the upper (furthest inward) edge formingthe join.

To make an ice cream product, unfrozen ice-cream mix 26A is placed intoa paper cup 26 and mounted onto motorised support 27. Valve 7 is openedto allow a portion of liquid gas to be poured into the cup 26 onto theice cream mix.

Motors 230, 25 and 27 which are linked to (and controlled by) a controlunit (not shown) are switched on so as to cause arm 22, agitationelement 24 and cup 26 to rotate.

The cup 26 may be provided with a removable splash ring 28 (see FIG. 1)shaped to sit against an upper part of the inside wall of vessel 26 andextend above the lip of vessel 26. Splash ring 28 reduces the incidenceof spillage of confectionary mix or liquid gas out from the cup 26during mixing, it also reduces/prevents said spillage onto the upperportion of the vessel. This is beneficial where the ice cream mix isconsumed directed from the cup 26 as it provides a clean inner rim whichmakes the cup (with product) look more aesthetically pleasing.

Although it is preferred that the vessel 26 is a paper cup or otherdisposable or once time item, it may take other forms, e.g. comprisedfrom plastic or metal and may be washed and reused.

Rather than using spring 31 other forms of biasing means may be used,for example, the agitating element may be formed, in part or whole, froma resiliently flexible material arranged to resiliently flex when theagitating element contacts the vessel wall.

The agitating element could take other forms, e.g. such as any of themixing element commonly used with food mixers. Further it could take theform of a spoon like element and be replaceable/disposable, e.g. used asa one time piece which is then used to consume the product.

Although it is generally expected that the liquid gas is poured into thevessel, in other embodiments, the liquid gas may poured or otherwisedirected around the outside of the vessel wall. The agitation elementcan still function as before, scraping frozen mix from the inside wallof the vessel and mixing it in with the reset of the unfrozen product.

Any other suitable liquid gas may be used instead of liquid nitrogen.

Although in the above example the agitating element is caused to moverelative to the vessel, in an alternative embodiment the vessel may becaused instead to move relative to the agitator. Further alternatively,the relative movement may be achieved through movement of both agitatorand vessel.

In alternative embodiments, the reservoir 4 may be omitted such thatliquid gas flows directly from the dewar 1 via a conduit to the vessel26 under control of a valve.

FIG. 5 illustrates an ice cream cart incorporating the above describedapparatus. Like parts will be given like numbers. The cart may bemotorised or otherwise. Dewer 4 feeds liquid gas via conduit 3 to tworeservoirs 4 serving two mixers 20 and corresponding vessels 26 whichsit on a work surface on top of the cart. In order to allow multipleservings confectionary product serving to made simultaneously. Dewer 4,which is carried in the cart is sized to supply sufficient volume ofliquid gas as is expected for a days trading. It can be refilled at thebeginning/end of the day by larger commercial vessels 40A 40B.

Also held within the cart is a refrigerated keg storing unfrozenconfectionary mix. A pipe 51 carries pumped mix from the keg 50 fordispensing into cups 26. Control of the flow of mix through pipe 51 isprovided by a valve, in the form of a hand held trigger tap at the freeend of the pipe 51. Keg 51 is held within a refrigerated chamber 60. Thechilling of chamber 60 is provided by piping cold vented gas which hasevaporated in reservoirs 4 and passed out of vents 9, via conduit 61into chamber 60.

1. A method of making a frozen confectionary product in which anunfrozen confectionary mix, agitated within a vessel, is cooled andfrozen by a liquid gas; wherein an agitator agitating the unfrozenconfectionary mix has a motion which comprises repeatedly drawing theagitator against an inside wall of the vessel.
 2. A method according toclaim 1 wherein the vessel is rotated in order that a subsequent motioncauses the agitator to draw against a different portion of the insidewall of the vessel.
 3. A method according to claim 1 wherein theagitator is drawn downwardly towards the base of the vessel.
 4. A methodaccording to claim 1 wherein the motion comprises an opposing movementin which the agitator moves away from the inside wall of the vessel. 5.A method according to claim 3 wherein the motion comprises an opposingupward movement in which the agitator moves away from the inside wall ofthe vessel.
 6. A method according claim 1 wherein in addition to themotion, the agitator is caused to rotate about its primary axis. 7-14.(canceled)
 15. A method according to claim 1 wherein the liquid gas isdelivered into the vessel.
 16. A method of making a frozen confectionaryproduct in which an unfrozen confectionary mix, agitated within avessel, is cooled and frozen by a liquid gas: characterised in that anagitator agitates the mix with a cyclic motion comprising: a downwardmovement through the confectionary mix towards the base of the vesselwhich moves frozen confectionary mix from an inner surface of the vesseltowards the base of the vessel; and an upward movement which movesunfrozen confectionary mix towards the surface of the confectionary mix;there further being a transversal movement such that the upward anddownward movements do not occur within the same part within the vessel.17. A method according to claim 16 wherein the cyclic motion comprises:a downward movement running proximate to an inside wall of the vessel;and that during the upward movement the agitator runs nearer the centreof the vessel as compared with the downward movement.
 18. A methodaccording to claim 17 wherein in the downward movement the agitatorcontacts the inside wall of the vessel.
 19. A method according to claim16 wherein the agitator also rotates about its primary axis.
 20. Amethod according to claim 16 wherein the vessel rotates.
 21. Apparatusfor making a frozen confectionary product comprising: an agitator drivento agitate a confectionary mix within a vessel; and means to supply aliquid-gas to cool and freeze the confectionary mix within the vessel,wherein the agitator is driven to be repeatedly drawn against an innerwall of the vessel.
 22. Apparatus according to claim 21 for making asingle portion of a frozen confectionary product.